The closest prior art is believed to be U.S. Pat. No. 4,440,122, issued to Roger D. Theobald, on Apr. 3, 1984, and entitled "Model Airplane Engine Starter". The contents thereof is incorporated herein by reference thereto. Particular reference is made to the prior art discussion contained therein, in Column 1 thereof and to the structure disclosed and claimed therein.
The device shown in the above Theobald patent constitutes a definite contribution to the art in that it positively precludes running of the engine in reverse, and in that the starter spring automatically engages the propeller and becomes energized when the latter is rotated in a contra-normal direction. Extended usage thereof has shown, however, that the connector member which connects the drive shaft to the propeller tends, upon occasion, to become loose and to slip, with the result that although the engine continues to operate properly, the propeller is no longer adequately driven because the connector member slips relative to the drive plate carried by the drive shaft. When the engine is shut off or runs out of fuel, the rapidly rotating propeller tends to continue to rotate. Since this tendency is directed in a direction opposite to that in which the propeller-securing nut tightens, the nut is urged by the propeller to turn toward a loosened position, causing the propeller to be held in a less-secured relation against the drive plate. As a consequence, power is lost initially and finally, the propeller may not be driven at all.